scholarly journals Mutational inactivation of Apc in the intestinal epithelia compromises cellular organisation

2020 ◽  
Vol 134 (2) ◽  
pp. jcs250019 ◽  
Author(s):  
Helena Rannikmae ◽  
Samantha Peel ◽  
Simon Barry ◽  
Takao Senda ◽  
Marc de la Roche
Keyword(s):  
Cell Proliferation ◽  
Wnt Pathway ◽  
Regulatory Element ◽  
Microtubule Dynamics ◽  
Intestinal Epithelial ◽  
Pathway Activity ◽  
Intestinal Epithelia ◽  
Epithelial Morphology ◽  
Effector Pathways

ABSTRACTThe adenomatous polyposis coli (Apc) protein regulates diverse effector pathways essential for tissue homeostasis. Truncating oncogenic mutations in Apc removing its Wnt pathway and microtubule regulatory domains drives intestinal epithelia tumorigenesis. Exuberant cell proliferation is one well-established consequence of oncogenic Wnt pathway activity; however, the contribution of other deregulated molecular circuits to tumorigenesis has not been fully examined. Using in vivo and organoid models of intestinal epithelial tumorigenesis we found that Wnt pathway activity controls intestinal epithelial villi and crypt structure, morphological features lost upon Apc inactivation. Although the Wnt pathway target gene c-Myc (also known as Myc) has critical roles in regulating cell proliferation and tumorigenesis, Apc specification of intestinal epithelial morphology is independent of the Wnt-responsive Myc-335 (also known as Rr21) regulatory element. We further demonstrate that Apc inactivation disrupts the microtubule cytoskeleton and consequently localisation of organelles without affecting the distribution of the actin cytoskeleton and associated components. Our data indicates the direct control over microtubule dynamics by Apc through an independent molecular circuit. Our study stratifies three independent Apc effector pathways in the intestinal epithelial controlling: (1) proliferation, (2) microtubule dynamics and (3) epithelial morphology.This article has an associated First Person interview with the first author of the paper.

Requirement of Notch activation during regeneration of the intestinal epithelia

2009 ◽  
Vol 296 (1) ◽  
pp. G23-G35 ◽  
Author(s):  
Ryuichi Okamoto ◽  
Kiichiro Tsuchiya ◽  
Yasuhiro Nemoto ◽  
Junko Akiyama ◽  
Tetsuya Nakamura ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Cell Differentiation ◽  
Epithelial Cells ◽  
Notch Signaling ◽  
Tissue Regeneration ◽  
Intestinal Epithelial Cells ◽  
Intestinal Epithelial ◽  
Intestinal Epithelia ◽  
Notch Activation

Notch signaling regulates cell differentiation and proliferation, contributing to the maintenance of diverse tissues including the intestinal epithelia. However, its role in tissue regeneration is less understood. Here, we show that Notch signaling is activated in a greater number of intestinal epithelial cells in the inflamed mucosa of colitis. Inhibition of Notch activation in vivo using a γ-secretase inhibitor resulted in a severe exacerbation of the colitis attributable to the loss of the regenerative response within the epithelial layer. Activation of Notch supported epithelial regeneration by suppressing goblet cell differentiation, but it also promoted cell proliferation, as shown in in vivo and in vitro studies. By utilizing tetracycline-dependent gene expression and microarray analysis, we identified a novel group of genes that are regulated downstream of Notch1 within intestinal epithelial cells, including PLA2G2A, an antimicrobial peptide secreted by Paneth cells. Finally, we show that these functions of activated Notch1 are present in the mucosa of ulcerative colitis, mediating cell proliferation, goblet cell depletion, and ectopic expression of PLA2G2A, thereby contributing to the regeneration of the damaged epithelia. This study showed the critical involvement of Notch signaling during intestinal tissue regeneration, regulating differentiation, proliferation, and antimicrobial response of the epithelial cells. Thus Notch signaling is a key intracellular molecular pathway for the proper reconstruction of the intestinal epithelia.

The influence of protein fractions from bovine colostrum digested in vivo and in vitro on human intestinal epithelial cell proliferation

2014 ◽  
Vol 81 (1) ◽  
pp. 73-81 ◽  
Author(s):  
Alison J Morgan ◽  
Lisa G Riley ◽  
Paul A Sheehy ◽  
Peter C Wynn
Keyword(s):  
Cell Proliferation ◽  
Epithelial Cell ◽  
Proliferative Activity ◽  
Intestinal Epithelial Cell ◽  
Bovine Colostrum ◽  
Intestinal Epithelial ◽  
Epithelial Cell Proliferation ◽  
Human Intestinal Epithelial Cell

Colostrum consists of a number of biologically active proteins and peptides that influence physiological function and development of a neonate. The present study investigated the biological activity of peptides released from first day bovine colostrum through in vitro and in vivo enzymatic digestion. This was assessed for proliferative activity using a human intestinal epithelial cell line, T84. Digestion of the protein fraction of bovine colostrum in vitro was conducted with the enzymes pepsin, chymosin and trypsin. Pepsin and chymosin digests yielded protein fractions with proliferative activity similar to that observed with undigested colostrum and the positive control foetal calf serum (FCS). In contrast trypsin digestion significantly (P<0·05) decreased colostral proliferative activity when co-cultured with cells when compared with undigested colostrum. The proliferative activity of undigested colostrum protein and abomasal whey protein digesta significantly increased (P<0·05) epithelial cell proliferation in comparison to a synthetic peptide mix. Bovine colostrum protein digested in vivo was collected from different regions of the gastrointestinal tract (GIT) in newborn calves fed either once (n=3 calves) or three times at 12-h intervals (n=3 calves). Digesta collected from the distal duodenum, jejunum and colon of calves fed once, significantly (P<0·05) stimulated cell proliferation in comparison with comparable samples collected from calves fed multiple times. These peptide enriched fractions are likely to yield candidate peptides with potential application for gastrointestinal repair in mammalian species.

scholarly journals Intestinal growth-promoting properties of glucagon-like peptide-2 in mice

1997 ◽  
Vol 273 (1) ◽  
pp. E77-E84 ◽  
Author(s):  
C. H. Tsai ◽  
M. Hill ◽  
S. L. Asa ◽  
P. L. Brubaker ◽  
D. J. Drucker
Keyword(s):  
Cell Proliferation ◽  
Fold Increase ◽  
Crypt Cell ◽  
Saline Control ◽  
Intestinal Epithelial ◽  
Intestinal Growth ◽  
Crypt Cell Proliferation ◽  
Term Administration ◽  
Glucagon Like Peptide

Glucagon-like peptide-2 (GLP-2) has been shown to promote intestinal epithelial proliferation. We studied crypt cell proliferation, enterocyte cell death, and feeding behavior in GLP-2-treated mice. GLP-2 had no effect on food consumption [7.7 +/- 0.3 vs. 8.0 +/- 0.4 g/day, saline (control) vs. GLP-2-treated mice, P = not significant]; however, GLP-2 increased the crypt cell proliferation rate (46.0 +/- 1 vs. 57 +/- 5%, control vs. GLP-2, P < 0.01) and decreased the enterocyte apoptotic rate (5.9 +/- 0.7 vs. 2.8 +/- 0.2% apoptotic cells, control vs. GLP-2, P < 0.05) in small bowel (SB) epithelium. GLP-2 induced a significant increase in SB weight (1.3- to 1.75-fold increase over control, P < 0.05 to P < 0.001) in mice 1-24 mo of age. Increased SB weight was maintained after daily administration of GLP-2 to mice for 12 wk, and cessation of GLP-2 administration in older mice led to regression of (increased) SB weight and mucosal height. These observations suggest that GLP-2 regulates both cell proliferation and apoptosis and promotes intestinal growth after both short- and long-term administration in vivo.

Neonatal growth and regeneration of β-cells are regulated by the Wnt/β-catenin signaling in normal and diabetic rats

2010 ◽  
Vol 298 (2) ◽  
pp. E245-E256 ◽  
Author(s):  
Florence Figeac ◽  
Benjamin Uzan ◽  
Monique Faro ◽  
Noura Chelali ◽  
Bernard Portha ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Wnt Pathway ◽  
Diabetic Rats ◽  
Β Cells ◽  
Β Cell ◽  
Ductal Cells ◽  
Gsk 3Β ◽  
Canonical Wnt

Wnt/β-catenin signaling is critical for a variety of fundamental cellular processes. Here, we investigated the implication of the Wnt/β-catenin signaling in the in vivo regulation of β-cell growth and regeneration in normal and diabetic rats. To this aim, TCF7L2, the distal effector of the canonical Wnt pathway, was knocked down in groups of normal and diabetic rats by the use of specific antisense morpholino-oligonucleotides. In other groups of diabetic rats, the Wnt/β-catenin pathway was activated by the inhibition of its negative regulator GSK-3β. GSK-3β was inactivated by either LiCl or anti-GSK-3β oligonucleotides. The β-cell mass was evaluated by morphometry. β-cell proliferation was assessed in vivo and in vitro by BrdU incorporation method. In vivo β-cell neogenesis was estimated by the evaluation of PDX1-positive ductal cells and GLUT2-positive ductal cells and the number of β cells budding from the ducts. We showed that the in vivo disruption of the canonical Wnt pathway resulted in the alteration of normal and compensatory growth of β-cells mainly through the inhibition of β-cell proliferation. Conversely, activation of the Wnt pathway through the inhibition of GSK-3β had a significant stimulatory effect on β-cell regeneration in diabetic rats. In vitro, GSK-3β inactivation resulted in the stimulation of β-cell proliferation. This was mediated by the stabilization of β-catenin and the induction of cyclin D. Taken together, our results demonstrate the involvement of the canonical Wnt signaling in the neonatal regulation of normal and regenerative growth of pancreatic β-cells. Moreover, we provide evidence that activation of this pathway by pharmacological maneuvers can efficiently improve β-cell regeneration in diabetic rats. These findings might have potential clinical applications in the regenerative therapy of diabetes.

scholarly journals Sulfation of 25-hydroxycholesterol regulates lipid metabolism, inflammatory responses, and cell proliferation

2014 ◽  
Vol 306 (2) ◽  
pp. E123-E130 ◽  
Author(s):  
Shunlin Ren ◽  
Yanxia Ning
Keyword(s):  
Cell Proliferation ◽  
Lipid Metabolism ◽  
Inflammatory Responses ◽  
Regulatory Element ◽  
Intracellular Lipid ◽  
Nonalcoholic Fatty Liver ◽  
Key Enzyme ◽  
Intracellular Lipid Accumulation

Intracellular lipid accumulation, inflammatory responses, and subsequent apoptosis are the major pathogenic events of metabolic disorders, including atherosclerosis and nonalcoholic fatty liver diseases. Recently, a novel regulatory oxysterol, 5-cholesten-3b, 25-diol 3-sulfate (25HC3S), has been identified, and hydroxysterol sulfotransferase 2B1b (SULT2B1b) has been elucidated as the key enzyme for its biosynthesis from 25-hydroxycholesterol (25HC) via oxysterol sulfation. The product 25HC3S and the substrate 25HC have been shown to coordinately regulate lipid metabolism, inflammatory responses, and cell proliferation in vitro and in vivo. 25HC3S decreases levels of the nuclear liver oxysterol receptor (LXR) and sterol regulatory element-binding proteins (SREBPs), inhibits SREBP processing, subsequently downregulates key enzymes in lipid biosynthesis, decreases intracellular lipid levels in hepatocytes and THP-1-derived macrophages, prevents apoptosis, and promotes cell proliferation in liver tissues. Furthermore, 25HC3S increases nuclear PPARγ and cytosolic IκBα and decreases nuclear NF-κB levels and proinflammatory cytokine expression and secretion when cells are challenged with LPS and TNFα. In contrast to 25HC3S, 25HC, a known LXR ligand, increases nuclear LXR and decreases nuclear PPARs and cytosol IκBα levels. In this review, we summarize our recent findings, including the discovery of the regulatory oxysterol sulfate, its biosynthetic pathway, and its functional mechanism. We also propose that oxysterol sulfation functions as a regulatory signaling pathway.

scholarly journals SOX9 directly regulates IGFBP-4 in the intestinal epithelium

2013 ◽  
Vol 305 (1) ◽  
pp. G74-G83 ◽  
Author(s):  
Zhongcheng Shi ◽  
Chi-I Chiang ◽  
Toni-Ann Mistretta ◽  
Angela Major ◽  
Yuko Mori-Akiyama
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Epithelial Cells ◽  
Target Genes ◽  
Intestinal Epithelial Cells ◽  
Neutralizing Antibody ◽  
Intestinal Epithelial ◽  
Loss Of Function ◽  
Deficient Mice

SOX9 regulates cell lineage specification by directly regulating target genes in a discrete number of tissues, and previous reports have shown cell proliferative and suppressive roles for SOX9. Although SOX9 is expressed in colorectal cancer, only a few direct targets have been identified in intestinal epithelial cells. We previously demonstrated increased proliferation in Sox9-deficient crypts through loss-of-function studies, indicating that SOX9 suppresses cell proliferation. In this study, crypt epithelial cells isolated from Sox9-deficient mice were used to identify potential target genes of SOX9. Insulin-like growth factor (IGF)-binding protein 4 (IGFBP-4), an inhibitor of the IGF/IGF receptor pathway, was significantly downregulated in Sox9-deficient intestinal epithelial cells and adenoma cells of Sox9-deficient Apc Min/+ mice. Immunolocalization experiments revealed that IGFBP-4 colocalized with SOX9 in mouse and human intestinal epithelial cells and in specimens from patients with primary colorectal cancer. Reporter assays and chromatin immunoprecipitation demonstrated direct binding of SOX9 to the IGFBP-4 promoter. Overexpression of SOX9 attenuated cell proliferation, which was restored following treatment with a neutralizing antibody against IGFBP-4. These results suggest that SOX9 regulates cell proliferation, at least in part via IGFBP-4. Furthermore, the antiproliferative effect of SOX9 was confirmed in vivo using Sox9-deficient mice, which showed increased tumor burden when bred with Apc Min/+ mice. Our results demonstrate, for the first time, that SOX9 is a transcriptional regulator of IGFBP-4 and that SOX9-induced activation of IGFBP-4 may be one of the mechanisms by which SOX9 suppresses cell proliferation and progression of colon cancer.

scholarly journals Mutational inactivation of Apc in the intestinal epithelia compromises cellular organisation

2020 ◽  
Author(s):  
Helena Rannikmae ◽  
Samantha Peel ◽  
Simon Barry ◽  
Inderpreet Sur ◽  
Jussi Taipale ◽  
...  
Keyword(s):  
Wnt Pathway ◽  
Significant Advance ◽  
Epithelial Tissue ◽  
Molecular Architecture ◽  
Regulatory Domains ◽  
Intestinal Epithelia ◽  
Enterocyte Proliferation ◽  
Apc Mutations ◽  
Effector Pathways

AbstractThe tumour suppressor adenomatous polyposis coli (Apc) regulates diverse effector pathways essential for cellular homeostasis. Truncating mutations in Apc, leading to the loss of its Wnt pathway and microtubule regulatory domains, are oncogenic in human and murine intestinal epithelia and drive malignant transformation. Whereas uncontrolled proliferation via Wnt pathway deregulation is an unequivocal consequence of oncogenic Apc mutations, it is not known whether loss of its other control systems contribute to tumorigenesis. Here we employ in vitro models of tumorigenesis to unmask the molecular barriers erected by Apc that maintain normal epithelial homeostasis in the murine intestinal epithelia. We determine that (i) enterocyte proliferation, (ii) microtubule dynamics and (iii) epithelial morphology are controlled by three independent molecular pathways, each corrupted by oncogenic Apc mutations. The key result of the study is to establish that Apc regulates three individual biological fates in the intestinal epithelia, through three distinct effector pathways, a significant advance to our understanding of normal tissue homeostasis, the molecular architecture of epithelial tissue and the aetiology of intestinal cancer.

scholarly journals Rack1 function in intestinal epithelia: regulating crypt cell proliferation and regeneration and promoting differentiation and apoptosis

2018 ◽  
Vol 314 (1) ◽  
pp. G1-G13 ◽  
Author(s):  
Zhuan-Fen Cheng ◽  
Reetesh K. Pai ◽  
Christine A. Cartwright
Keyword(s):  
Cell Proliferation ◽  
Paneth Cell ◽  
Cell Cycle Checkpoints ◽  
Crypt Cell ◽  
Colon Cells ◽  
Intestinal Epithelia ◽  
Crypt Cell Proliferation ◽  
Crypt Cells

Previously, we showed that receptor for activated C kinase 1 (Rack1) regulates growth of colon cells in vitro, partly by suppressing Src kinase activity at key cell cycle checkpoints, in apoptotic and cell survival pathways and at cell-cell adhesions. Here, we generated mouse models of Rack1 deficiency to assess Rack1’s function in intestinal epithelia in vivo. Intestinal Rack1 deficiency resulted in proliferation of crypt cells, diminished differentiation of crypt cells into enterocyte, goblet, and enteroendocrine cell lineages, and expansion of Paneth cell populations. Following radiation injury, the morphology of Rack1-deleted small bowel was strikingly abnormal with development of large polypoid structures that contained many partly formed villi, numerous back-to-back elongated and regenerating crypts, and high-grade dysplasia in surface epithelia. These abnormalities were not observed in Rack1-expressing areas of intestine or in control mice. Following irradiation, apoptosis of enterocytes was strikingly reduced in Rack1-deleted epithelia. These novel findings reveal key functions for Rack1 in regulating growth of intestinal epithelia: suppressing crypt cell proliferation and regeneration, promoting differentiation and apoptosis, and repressing development of neoplasia. NEW & NOTEWORTHY Our findings reveal novel functions for receptor for activated C kinase 1 (Rack1) in regulating growth of intestinal epithelia: suppressing crypt cell proliferation and regeneration, promoting differentiation and apoptosis, and repressing development of neoplasia.

scholarly journals Tight Junction Proteins Claudin-2 and -12 Are Critical for Vitamin D-dependent Ca2+ Absorption between Enterocytes

2008 ◽  
Vol 19 (5) ◽  
pp. 1912-1921 ◽  
Author(s):  
Hiroki Fujita ◽  
Kotaro Sugimoto ◽  
Shuichiro Inatomi ◽  
Toshihiro Maeda ◽  
Makoto Osanai ◽  
...  
Keyword(s):  
Vitamin D ◽  
Tight Junction ◽  
Active Form ◽  
Intestinal Epithelial ◽  
Tight Junction Proteins ◽  
Dihydroxyvitamin D ◽  
Intestinal Epithelia ◽  
Junction Proteins

Ca2+ is absorbed across intestinal epithelial monolayers via transcellular and paracellular pathways, and an active form of vitamin D3, 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3], is known to promote intestinal Ca2+ absorption. However, the molecules driving the paracellular Ca2+ absorption and its vitamin D dependency remain obscure. Because the tight junction proteins claudins are suggested to form paracellular channels for selective ions between neighboring cells, we hypothesized that specific intestinal claudins might facilitate paracellular Ca2+ transport and that expression of these claudins could be induced by 1α,25(OH)2D3. Herein, we show, by using RNA interference and overexpression strategies, that claudin-2 and claudin-12 contribute to Ca2+ absorption in intestinal epithelial cells. We also provide evidence showing that expression of claudins-2 and -12 is up-regulated in enterocytes in vitro and in vivo by 1α,25(OH)2D3 through the vitamin D receptor. These findings strongly suggest that claudin-2- and/or claudin-12-based tight junctions form paracellular Ca2+ channels in intestinal epithelia, and they highlight a novel mechanism behind vitamin D-dependent calcium homeostasis.

scholarly journals Repression of c-Kit and Its Downstream Substrates by GATA-1 Inhibits Cell Proliferation during Erythroid Maturation

2005 ◽  
Vol 25 (15) ◽  
pp. 6747-6759 ◽  
Author(s):  
Veerendra Munugalavadla ◽  
Louis C. Dore ◽  
Bai Lin Tan ◽  
Li Hong ◽  
Melanie Vishnu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
Regulatory Element ◽  
Cytokine Signaling ◽  
Cycle Arrest ◽  
Erythroid Maturation ◽  
Signaling Components

ABSTRACT Stem cell factor (SCF), erythropoietin (Epo), and GATA-1 play an essential role(s) in erythroid development. We examined how these proteins interact functionally in G1E cells, a GATA-1− erythroblast line that proliferates in an SCF-dependent fashion and, upon restoration of GATA-1 function, undergoes GATA-1 proliferation arrest and Epo-dependent terminal maturation. We show that SCF-induced cell cycle progression is mediated via activation of the Src kinase/c-Myc pathway. Restoration of GATA-1 activity induced G1 cell cycle arrest coincident with repression of c-Kit and its downstream effectors Vav1, Rac1, and Akt. Sustained expression of each of these individual signaling components inhibited GATA-1-induced cell cycle arrest to various degrees but had no effects on the expression of GATA-1-regulated erythroid maturation markers. Chromatin immunoprecipitation analysis revealed that GATA-1 occupies a defined Kit gene regulatory element in vivo, suggesting a direct mechanism for gene repression. Hence, in addition to its well-established function as an activator of erythroid genes, GATA-1 also participates in a distinct genetic program that inhibits cell proliferation by repressing the expression of multiple components of the c-Kit signaling axis. Our findings reveal a novel aspect of molecular cross talk between essential transcriptional and cytokine signaling components of hematopoietic development.

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